US Attorney Preet Bharara has reportedly subpoenaed the
hospital's owner, the State University of New York, for its
emails and other records of communication with City Hall —
specifically with de Blasio and five of his top aides.

A source close to SUNY told the Daily News that de Blasio seems
to be "the clear target."

During his mayoral campaign in 2013, de Blasio had fought to keep
the state-run hospital open, despite SUNY's efforts to close and
sell it. But shortly after taking office, de Blasio struck a deal
that left the property with some guaranteed healthcare services,
but not enough to make it a full hospital.

Later,
de Blasio backed a plan by the Fortis Property Group to
demolish the hospital buildings and redevelop the site into low-
to middle-income apartments, according to The Real Deal.

Bharara's office is now searching for
evidence of malfeasance within de Blasio's administration
regarding the hospital's sale, the New York Post reported. The
subpoena also seeks communication records dating back to de
Blasio's tenure as the city's public advocate, when he first
began campaigning to keep the hospital open.

De Blasio's spokesman Eric Phillips told the Daily News the
mayor's office is unaware of an investigation by Bharara into the
hospital's sale.

The subpoena comes on the heels of a separate federal corruption
probe into de Blasio's fund-raising activities. Four New York
Police Department officials and two businessmen have been
arrested so far in the investigation, which has been underway
for more than two years.